Method and apparatus for constructing alpha concrete caisson



Aug. 8, 1933.

T. M CAULEY, JR

METHOD AND APPARATUS FOR CONSTRUCTING A CONCRETE CAISSON Filed May 4, 1931 2 Sheets-Sheet 1 cc u JR 1,921,236

METHOD AND APPARATUS FOR CONSTRUCTING A CONCRETE CAISSON Amig.

2 Sheets-Sheet 2 Filed May 4, 1931 Patented Aug. 8, 1933 UNITED sra eater nn surnames roe con sensor-rue A eosioas'rn caisson 2 Claims.

The invention relates to a new and useful improvement designed to overcome difficulties experienced in introducing concrete columns or foundation piers through underground strata of quick sand or other loose water bearing material under conditions that heretofore made it necessary to resort to expensive and dangerous methods, especially where such quick sand or other loose water bearing material is under high pressures from superposed strata of earth or rocks, buildings andthe like.

The primary object of the invention is to provide an improved method and apparatus for use in carrying out the method by which concrete walled caissons may be readily and economically constructed through underlying strata of quick sand and other unstable water bearing material. 7

Other objects of the invention will appear from the following description which is directed to the preferred form of the invention as depicted in the drawings forming a part of the specification, the

features of novelty being set forth in the appended claims. a I I In the said drawings:

Fig. 1 is a vertical, sectional view taken through a re-enforced caisson opening showing strata of earth, shale, hardpan and the like with a stratum of sand at the bottom of the caisson opening through which the caisson is to be constructed, and illustrating the step of introducing the tool f or piercing the sand stratum preparatory to introducing the concrete re-eniorcing or caisson wall portions therein. In this view the apparatus ready for piercing the sand stratum is shown in position and the path of the appara tus through the sand stratum is. indicated by dotted lines. g V

Fig. 2 is an enlarged, broken detailed view, showin a section of the apparatus of Fig. 1, the sand piercing apparatus being shown in a position where the sand stratum has beenpartially penetrated. In this view the connections T introduced on the interior of the device of Fig.

2 :for introducing a plastic or semi-plastic concrete mixture into the opening previously formed by the apparatus in the sand stratum, the connections for supplying theconcrete to the upper end of the apparatus in this View being shown in elevation.

Fig. 4 is a broken, sectional detailed view show-v ing the same parts as shown in Fig. 3, illustrating the manner in which the assembled apparatus is retracted from the hole inthe sand stratum during the operation of filling the same with concrete.

Fig.5 is a transverse view 'takenflthrough a plurality of the caisson wall portions, or cores on line 55 of Figs. 5 andfi and looking in the direction indicated by the arrows, the View showing the unexcavated inner core.

Fig. 6 is a broken, verticaLsectionalview taken through a completed concrete walled caisson bore, theview being taken approximately on the line 6--6 of Fig. 5 before the excavation of the inner core and looking in the direction indicated by the arrows., I

Fig. '7 is a broken, vertical sectional view sim ilar to the view in Fig. 6 showing the condition of the concrete caisson wall adjacent the sand stratum after the removal of the sand core'which latter is shown in position before removal in Fig.6.v I

Fig. 8 is a broken, transverse sectional view of. that portion of'the caisson wall through the sand stratum shown in Figs. 6 and 7 after the re rnovalof the original sand core and illustrating them'anner of filling the hollow interior of'the excavating caisson opening with a mass concrete core. v I

Fi 9 is, a'detailed, transverse sectional view on line 9-9 of Fig. 8 looking in the direction 111% dicated by the arrows,

My invention is particularly adapted to the construction of the underground caisson which 'makes possible the placing of concrete piers or columns or" appreciable diameter that are construct'ed underneath buildings and other heavy structures and are designed to extend through underlying strata of sand and loose materials downto a firm or supporting stratum asbed rock.

One of the common uses to which my invention may be put is in constructing a caisson wallfor receiving mass concrete piers or columns for supporting extremely tall and heavy buildings where there is. an accumulation of such weight that it essential that the supporting substructure shall rest upon a stratum of underlying rock or other very firm substance.

I have shown my invention particularly applied inthe present embodiment to the construction of a caisson Wall and pier therein in a condition as illustrated, for example, in Fig. 1 where at the bottom of a basement or sub-basement excavation as indicated by the reference character 10, there is an underlying section or strata. of comparatively firm earth as designated by the reference character 11 which may consist of different layers of soil, hardpan, clay or gravel beds of a condition that does not interpose serious obstacles to excavation and re-enforcement of the walls of the caisson excavation by ordinary methods, while underlying the firm stratum 11, there is a stratum of loose quick sand or other water bearing material 12 that overlies the rock stratum 13 upon the top of which it is desired to construct the caisson column. V

In Fig. 1 I illustrate a conventional form of lining or supports for the Walls of the stratum 11. These supports or lining members may be firm wood or metallic pieces of suitable length, width and thickness and if it were desired only to extend the caisson opening through comparative- 1y firm earth materials, such as soil, clay or hard pan 11, no particular problems would be involved since the caisson opening, usually of a cir- Cular shape,,may be formed by ordinary digging or excavating methods and as the opening proceeds downwardly, the walls thereof may be reenforccd by the planking or lining materials designated by reference character 14, placed in barrel stave formation and held in position by suitable inside supporting metallic rings 15. However, when the sand stratum 12 at the bottom, which may run anywhere from ten or twelve feet to twenty five or thirty feet or more before th ro k struturn. 13 is r a hed... is o a ry loose, wet character and'especially where extraordinary pressures are developed from adjoining buildings,

there may be a condition developed that makes it impossible to proceed by the ordinary excavating and lining methods to the solid stratum at the bottom of the caisson opening. Sometimes these method of finishing the excavation in the bottom of the caisson through the loose stratum of water bearing'sand or other materials, by which method an air tight open bottomed metallic bell-shaped compartment is lowered into the bot-v bozn of the caisson and the excavating is continued through the same maintained under an air pressure suff cient to counter-act the outside pressure tending to force the sand or other water .bearing materials into the caisson opening. The

compressed air method, by reason of the expensive apparatus employed andthe extremely dangerous conditions under which men must labor in the compartment containing air underpressure, renders the latter method highly objectionable as being very dangerous and expensive.

In the construction of the foundation supporting structure for comparatively large, tall, modern buildings, it is common, at the bottom of the basement or subbasement thereof, to providea large number of caisson openings at spaced in-' tervals for receiving and supporting the usua piers or columns for carrying the building load.

In carrying out my improved method, I excavate the caisson opening through the upper strata of materials and supply the re-enforcement 14 to the wall thereof to a point some distances above the point where a difiicult sand stratum is found by suitable exploration. I then continue the excavation and lining of the caisson opening by undercutting or widening downwardly in the manner indicated by the reference character l6, gradually bringing it to a point where the diameter of the opening as indicated at 17 will be of a sufficient width so that the inside diameterpf the concrete lined and supported caisson opening, when finished at the bottom of the opening through the loose water bearing sand or other materials, will correspond substantially to the desired diameter of the excavation or caisson opening at the top thereof. For example, assume that the diameter of the opening at the top, as designated by the reference character 18, may be five feet, I would undercut and line the opening at the point 17 as illustrated in Fig. 1 where it would have a diameter of say seven feet or a little less and this would provide sufficient room for manipulation of the drilling device to be hereinafter described for penetrating the stratum of sand and for introducing therein the concrete lining wall as hereinafter described.

Below the point 17, the caisson opening will be constructed in the ordinary manner and the wall lined as the opening progresses downwardly until such time as the layer of water bearing sand or other loose water bearing material is reached as designated by the reference character 12. When this stratum is reached and the ordinary method of digging and lining as hereinbefore described, will not suffice, I introduce on the interior of the caisson opening, a drilling or penetrating device which is shown in detail in Figs. 1 and 2. It comprises a metallic tube of a convenient diameter, as three and one-half or four inches and it may be of any desired length to operate in a known condition of caisson construction but it should at any rate be long enough to reach from the top to the bottom of the stratum of quick sand .or other water bearing materials. Such a tube is designated by the reference character 20 and it will preferably be provided throughout its length with a plurality of perforations, designated by reference character 21. These may be distributed spirallyv around the tube from end to end thereof at suitable spaced distances as indicated in the drawings. The upper end of the tube 20 will be interiorally threaded to take a suitable plug or closure cap 22 threaded at 23 and provided with a perforated nipple 24 adaptedto receive a suitable, preferably flexible, water tube or hose 25 clamped to the nipple by clamp 26 for supplying water under suitable head or pressure from some source, preferably on the exterior of the caisson opening. The lower extremity of the tube 20will be left open as illustrated in Fig. 2 and the tube with the hose attached may be lowered into the caisson opening from the top bya suitable cord or cable as designated by reference character 27,

the latter to be attached by a suitable hook 28 u cavated to -the top of the sand stratum 12 and when the water is turned into the tube, the pressure and current of the water at the bottom of the tube will soften and wash away the loose sand particles so that the tube may be readily lowered through the sand stratum substantially by its own weight completely piercing the sand stratumand finally resting on the rock stratum 13 below.

It is found, in fact, that even when the water under slight pressure is plentifully supplied through the hose 25, the tube 20 will of its own weight pass through the sand stratum and may require some retarding action in so passing by means of the controlling wire rope or cord 27 so that no difficulty whatver will be experienced in causing the tube 20 to readily pierce the sand stratum and come to a position of rest upon the rock stratum 13 below.

During the downward passage or boring movement of the tube 20, jets of water will, of course, pass readily from the tube through the spirally arranged openings 21 thus softening the adjacent sand and slightly enlarging the effective opening around the tube as indicated at 31 in Figs. 2 and 3.

When the tube 20, equipped as illustrated in Fig. 2 has pierced the sand stratum 12 with the lower end thereof resting upon the rock stratum 13, as illustrated in Fig. 3, the water supply through the hose 25 will be shut off and the hose with its connector 22 disconnected and a concrete supply hose or tube, preferably of a somewhat larger interior bore, as designated by reference character 33, terminating in an attached metallic pipe 34, the latter being substantially the length of the tube 20, will be lowered into the caisson opening with the tube 34 telescoping the interior of the tube 20, as illustrated in Figs.'3 and 4.

The function of the tube 33, 34 is to introduce a semi-liquid or wet plastic concrete mixture of sand and cement or analogous materials for forming a protective wall around the caisson opening through the quick sand stratum to protect the bore therethrough from outside pressure and water to facilitate the removal of the sand core in order to complete the excavation or caisson opening down to the bed rock stratum 13. As the plastic flowing concrete passes downward by gravity through the feed tube 33 and the me tallic tube 34 on the interior of the tube 20, the tube 20 with the concrete supply tube 34 connected thereto will be gradually raised so that the concrete designated by the reference character 35 will be deposited and form a substantially solid core as designated by the reference character 35, shown in the process of formation in F 4.

The synchronous raising of the tube 20 and the tube 34, as the bore made by this apparatus is filled with concrete, may be accomplished by providing the open end of the metalic tube 34 with an enlarged circular flange 37 adapted to rest upon the top of the tube 26 andinto which the lower end of the tube 33 will be screw threaded, as indicated at 38 Figs. 3 and 4.

The concrete core 36 will thus be formed of an integral piece from the bottom of the opening upon the rock stratum 13 to the top of the sand stratum as illustrated in Figs. 4, 5 and 6. It will be obvious that using a mixture of relatively free 1 flowing concrete in the supply tube 33, 34, an operator from the top of the shaft may determine by the flow of the concrete, the rate at which the tube 20 and the tube 34 may be withdrawn so that the opening through the sand stratum will be completely filled with a core of concrete as designated by reference character 36. When the opening made by the tube 20 has been completely filled with a core of concrete 36, the concrete supply pipe 33, 34 will be detached from the tube 20 and the process of introducing the tube 20 with its water supply will be repeated and this will be followed by the disconnection of the water supply device as hereinbefore described and the subsequent use of the concrete supply tubes 33, 34 until the entire periphery of the proposed caisson opening through the sand stratum will have been walled in with the closely positioned or juxtapositioned concrete cores 36, as shown in Figs. 5 and 6, when it will be seen that the closely positioned concrete cores 36 will form a substantially circular, closed, retaining wall through the sand stratum 12 with a sand core on the interior thereof as designated by'the reference character 40 in Fig. 5.

The concrete circular, retaining wall formed of the juxtapositioned concrete columns 36, after being permitted to set in the usual manner, will form a retaining wall of sufficient strength to withstand external pressure in the sand stratum and will also be sufficiently compact to exclude water, except inrelatively small quantities, particularly when the sand stratum 12 is comparatively free of solid rocks or boulders of appreciable size.

Should the boring or piercing tube 20 on its way through the sand stratum 12 at any point encounter a solid rock or boulder embedded in the sand stratum, it would, of course, be necesrock in the bottom, after which the tool will be again introduced into the sand until it will pass the detached rock or boulder and the wall completed .in the manner before described. This procedure will, of course, result in the absence of the concrete core or cores below the rock or boulder whenthe process of forming the circular wall of concrete cores through the sand stratum is completed, and such procedure will, offer no difficulties in removing the interior sand core 49 down as far as the detached boulder or rock is located.

After the sand core is removed by ordinary excavating processes to thelocation of the detached rock or boulder previously encountered by the tube, the rock or boulder will be broken away or removed and the open space below the same to the bottom of the caisson opening upon the bed reel; 13 filled with concrete by the workmen while thedigging or excavating of the sand core is continued. If objectionable inflow of Water or water bearing sand under extraordinary pressures is encountered after the removal or breaking away of the detached rock or boulder, the open space between the concrete cores of the wall may be substantially closed by the driving downwardly of a wood plank or a strip of metal sheathing or piling that may be suitably braced against external pressures during the removal of the sand core down to the rock stratum practically co-extensive with.

away the boulder, the water drilling tube 20 may be still employed with advantage to block off the opening below the boulder in the following manner:

After proceeding as'before described to wall v off the caisson opening, except below the boulder,

the excavation of the earth, sand and other materials within the wall may proceed downwardly as far as possible toward the top of the boulder.

Under most conditions this may proceed until within a short space above the boulder or even until the boulder itself is reached. If, under these conditions, the boulder cannot be reached in excavating for removal or' breaking away or" thenecessary parts there the caisson opening below the boulder still be successfully excavated for the most part by the use of my improved water boring tube and concrete introducing tube by drilling irregularly around the outline of the boulder especially where it protrudes into the caisson opening only a part of the diameter of the proposed bore or shaft opening. The concrete cores will then be introduced as before described into the drilled openings so that that portion of the caisson wall be.ow boulder will conform substantially to the outline of the boulder, but 'it will be seen that it will have the effect of sealing the wall or the caisson opening and if it is impossible before this procedure to excavate all the way to the boulder on account of excessive pressures and abnormally loose and free flowing sand and'water, that irregular portion'oi the wall'thus "formed below the boulder will thus be sealed so that the excavating process may con tinue down to the boulder, the workmen breaking away any irregular part of the wall pro truding above the bould r, and the work of excavating may then continue downwardly from the boulder to the rock below leaving the caisson opening with its wall of concrete cores thus irregularly fcrmed below the boulder, from which it will be seen that unless the boulder should be the caisson opening, which will ordinarily not occur, a substantially irregular caisson opening may then be formed from theboulder to the bed rocl: suitable for all practical purposes after excavating the loose materials on the inside of the wall to permit the caisson opening to be filled with the necessary concrete to bed rock.

After'the caisson walls have been re-enforced by the concrete cores 3-5 as illustrated in Figs. 5 and 6 and the core 40 has been removed down to the bed rock stratum 13, the walls or the caisson opening through the uicksand stratum 12 will have'the appearance of the fOlLl illustrated in Fig. After the removal of the sand core 49, any objectionable leaks or openings left in the concrete r taining wall in the sand stratum will be closed by a workman applying the concrete with ordinary tools in the usual manner and the caisson opening will then be ready for the introduction of the final concrete to form the pieror colui which will be introduced in the usual or any do ed manner as designated by the refe nce character 45 in 8 to form the perman it concrete pier or column as'designated by the reference character 46' in Figs. 8 and 9.

From the above description, it'will be seen that I have provided a method and apparatus adapted to be used in caisson construction through a submerged stratum of quick sand'or other loose water bearing materials that may be successfully used at a moderate expenditure for-labor and materials even under the most difiicult conditions and pressures and that the mechanism employed is of a simple and economical character and not likely to get out of order, and which may be operated by a laborer having a reasonable degree of skill and efliciency, and that the concrete Coffer dam constructed with the apparatus and in accordance with the method herein described being of substantial concrete cores that may be positioned in circular formation around the walls of the proposed caisson opening through the diffucult strata of loose or water bearing materials, may be readily made elfective' to withstand the most severe pressures, since it is unnecessary to remove the interior core of the loose material until after the concrete has set to give the desired support and protection, and that after the substantial side walls or cofier dam, formed as herein described, has set, the proposed explored caisson bore or opening may be excavated safely and easily by any desired excavating apparatus.

Inorder that the invention might be under stood, the details of the preferred embodiment have been set forth with respect to both the apparatus and the method employed but itis not desired to be limited to such details except as set forth in the claims since it will be apparent that those skilled in the art may resort to various modifications of the apparatus and the method described without departing from the purpose or water bearing sand or other loose water bearing .iaterials lying upon a stratum of bed rock or other load sustaining material, which consists in first excavating and bracing the caisson opening through the stratum of relatively firm materials down to the stratum of water bearing 'sandor other relatively loose water bearing materials, and undercutting or enlarging a portion of the bore through the materials immediately above the stratum of water bearing sand or other relatively 'loose water bearing materials, then ing an enclosing wall or cofie'r dam-consisting of. a plurality of vertical juxtaposed concrete cor-es, lying substantially within the undercut portion or" the wall of the said bore andextending down to the firm stratum of material through the water bearing sand or other loose water bearing materials by the introduction of an .openended tube supplied on the interior thereof with water underfipressure to pierce the said loose stratum to wash the'said loosematerials out of: the tube, filling the tube with concrete, re-

moving the tube from the concrete core thus formed, removing the core of water bearing sand or other loose water bearing materials on the 3 inside of the wall or coller dam thus formed, and finally filling the entire caisson with concrete.

2. The e herein described method of constructa cai 6 .excavating'and bracing the caisson opening n1 through a stratum of relatively s through the stratum of relatively firm materials down to the stratum of Water bearing sand or other relatively loose Water bearing materials, then forming an enclosure comprising a plura1- ity of vertical juxtaposed concrete cores, forming substantially a continuation of the previously formed opening through the stratum of relatively firm materials and extending down to a firm stratum of material through the Water-bearing sand or other loose water bearing materials by the introduction of an open-ended tube supplied on the interior thereof with water under pres- 

